Pool-less auger-separator for materials of differing specific gravities

ABSTRACT

A machine for separating pieces of a heavier substance from pieces of a lighter substance both of which will sink in water, comprising an upwardly inclined trough having in it an auger upheld by the trough itself for carrying the pieces of heavier substance upwardly while the pieces of lighter substance which can be as large as lump coal are pushed by the force of turbulent, pool-less, free-flowing water out of an open lower end of the trough closely adjacent to the upper side of the auger.

United States Patent 1 1 Patch POOL-LESS AUGER-SEPARATOR FOR MATERIALS OF DIFFERING SPECIFIC GRAVITIES [76] Inventor: William D. Patch, c/o Bills Coal,

lnc., Welch, Okla. 74639 [22] Filed: Dec. 14, 1970 [21] Appl. No.: 97,837

Related US. Application Data [63] Continuation-impart of Ser. No. 78,256, Oct. 5, 1970,

abandoned.

[52] US. Cl. 209/460, 209/155, 209/485,

209/499 [51] Int. Cl B03b 3/30 [58] Field of Search 209]], 155, 162,

[56] References Cited UNITED STATES PATENTS 890,876 A 6/1908 Scaife 209/450 1,044,845 11/1912 Argall 209/464 1,714,007 5/1929 Endrezze 209/464 1,984,362 12/1934 Dickson.... 209/464 2,060,569 Greenlaw 198/213 X June 19, 1973 2,270,954 l/1942 McCloud et a1. 209/464 X 2,368,416 1/1945 Holt 209/172.5 2,460,802 2/1949 Bitzer 209/173 2,502,840 4/1950 Hayes 209/489 X 2,606,660 8/1952 Klepetko et a1. 209/173 X 2,635,104 4/1952 Chayen 209/173 UX 2,933,187 4/1960 Old et al. 209/464 FOREIGN PATENTS OR APPLICATIONS 8,526 3/1896 Great Britain 209/450 Primary ExaminerF rank W. Lu'tter Assistant Examiner-Ralph J. Hill Att0rneySchmidt, Johnson, Hovey and Williams [57] ABSTRACT A machine for separating pieces of a heavier substance from pieces of a lighter substance both of which will sink in water, comprising an upwardly inclined trough having in it an auger upheld by the trough itself for carrying the pieces of heavier substance upwardly while the pieces of lighter substance which can be as large as lump coal are pushed by the force of turbulent, p001- less, free-flowing water out of an open lower end of the trough closely adjacent to the upper side of the auger.

10 Claims, 4 Drawing, Figures Pmmmwm 3,139.91 1

INVENTOR. G7 m mg WILLIAM D. PATCH POOL-LESS AUGER-SEPARATOR FOR MATERIALS OF DIFFERING SPECIFIC GRAVITIIES CROSS-REFERENCE This application is a continuation-in-part of my application U. S. Ser. No. 078,256, filed Oct. 5, 1970, and entitled COAL SEPARATOR now abandoned.

FIELD OF THE INVENTION This invention is in the field of auger-separator machines for separating pieces of two substances of differ ing specific gravities from each other, when neither of the two substances will float in water.

DESCRIPTION OF THE PRIOR ART Prior art machines for this purpose have failed to achieve general use, in my opinion, because their auger-troughs have been so closed at their lower ends that the water cannot escape except over a weir and unfortunately a pool of substantially tranquil water is then formed at the lower end of the trough, defeating effectiveness.

I have discovered that the trough must have an open lower end permitting water to pass freely out to provide a forceful cascade of most un-tranquil poolless water turbulently tumbling down across the lower part of the auger in free-flow, as is vitally necessary to stir rock and coal pieces enough to allow the rock to sink below the coal, and the coal to be supported by the motion of the water.

Deep tranquil pools do not defeat use in the field of separating small particles such as fine sand because water spilling over a weir from a pool is forceful enough for carrying fine sand with it but would be far too weak a force to carry the larger pieces of coal if such a machine were used as a coal-frorn-rock separator.

Prior art machines have had augers mounted in rigid bearings and so when a rock gets between an auger flight and the trough-bottom the auger is wedged upward allowing a larger rock to also get in this position until the auger binds and stops. An impractical machine is the result.

Some attempts were made of patent record in the period which began about 75 years ago, and during a period of a little more than a decade at the turn of the century, to solve the problem of separating rock from coal by use of an auger, a trough, and water.

These attempts met with such limited success, in my opinion, that they were soon abandoned, whereby no method of this sort is today generally known of by the industry, and no economically practical solution has been offered.

Another mistake made by the earlier coal-rock separation experimenters was to make the trough so shallow in ratio to the diameter of the auger that the coal could not move across the top of the auger flights downwardly through the trough.

Still another mistake of coal-rock separation experimenters was to use open-centered auger flighting in the form of a spiral ribbon. With this construction, it was necessary for the coal to move downwardly in the trough, not across the top of an auger, but against the first impediment of portions of the conveyor flighting and against the second impediment of supporting braces extending from an axle out to the conveyor flighting and against a third impediment because the axle of the large diametered auger was right in the way of coal flow which, in earlier coal-rock machines, must be a flow taking place through the center opening of the auger and hence on the same level in the trough as the axle at the end of the auger.

Open-centered conveyors are more suitable for a mineral classifier than for a lump coal separating machine because the smaller-sized particles in mineral classifiers are much more adapted to flow between the outer spiral portions of an open-centered ribbon conveyor, whereas lump coal would tend to move only extremely slowly in such tight confined space.

Conversely, if an open-centered. conveyor were used in a lump coal separator, then the conveyor would have to be so extremely large to have a sufficient space for coal to flow downwardly through the opening in the flighting, that the cost of the conveyor would be impractical.

SUMMARY OF THE INVENTION A machine for separating pieces of a heavier substance from pieces of a lighter substance both of which will sink in water, comprising an upwardly inclined trough having in it an auger upheld by the trough itself for carrying the pieces of heavier substance upwardly while the pieces of lighter substance which can be as large as lump coal are pushed by the force of turbulent, pool-less, free-flowing water out of an open lower end of the trough closely adjacent to the upper side of the auger.

The water turbulence or water motion is carefully regulated partly by its rate of input and partly by the angle the trough inclines with respect to the horizontal. The water turbulence or water motion is sufficient to cause the coal to be supported by the moving turbulent water, like dirt that would ordinarily settle issupported by the motion of stirred water, but the water motion is kept not too high so as to be not sufiicient to cause the rock to be supported by the moving water like the coal is.

The combination described in which the relative proportions of the auger diameter in inches to the trough length are approximately in the ratio of five to the figure of: 40 multiplied by 112.

The combination in which the auger is unsupported except at its upper end where it is connected to a motor by a universal joint and bearings whereby there are no bearings at the lower end of the auger to be damaged by abrasive materials and water, and whereby the auger is free to move upwardly transversely of itself to prevent binding if a piece of rock gets caught between the auger and the bottom of the trough.

The combination described further provided with a feeler movably mounted in the trough and adapted to move in response to excessive material in the trough and operably correlated with the switch controlling power means regulating the inflow of material so that excessive flow of material is stopped whenever there is an excessive amount of material in the trough.

The combination described in which the auger revolves at less than 200 revolutions per minute.-

BRIEF DESCRIPTION OF DRAWING I FIG. 11 is a side elevation of the machine for material separation of this invention showing a trough, a forward side portion of which is broken away showing the interior, water surfaces being shown in dotted lines, a

portion of a conveyor delivering mixed raw material to the machine being broken away, and portions of the length of the conveyor being broken away.

FIG. 2 is a sectional view taken along the line 22 of FIG. 1.

FIG. 3 is a top view of the conveyor taken along the line 3-3 of FIG. 1 in a direction looking at a right angle to the length of the trough. Portions of the length of the conveyor are broken away and materials and water are not shown in FIG. 3.

FIG. 4 is a wiring diagram of the material supply motor and raw material supply rate control feeler switch.

DESCRIPTION OF THE PREFERRED EMBODIMENT The pool-less separating machine of this invention is generally indicated at and has an elongated auger having a shaft 22 carrying a drive pulley 24 driven by a motor and pulley assembly 26.

The inclination of the auger from its lower end to its upper end is an acute angle of 5 preferably, but 20 will also work, with respect to the horizontal for cooperation with an auger speed of 50 revolutions per minute on the scale represented by an auger having a flight diameter of 5 or 5% inches.

The auger 20 is complementally configured to be closely received generally within a semi-circular bottom zone of an elongated auger housing or trough which extends parallel to the straight auger 20. The auger shaft extends beyond the upper end of the trough. For a 5 or 5% inch diametered auger, a trough length of 40 feet is workable and with a trough inclination of 5 with respect to the horizontal, will separate 40 tons of coal an hour at to revolutions per minute and with an auger flight spacing of 3 inches.

A mixture of rocks and coal are delivered through a delivering means or funnel disposed above a midpoint between the ends of the trough to define a material delivery point at arrow 92.

The lower end of the trough is completely open between two parallel sides 96 of the trough which extend from approximately the level of the center of the auger shaft 22, at any transverse cross-section of the trough, upwardly to the tops of the 24 inch high walls 96 which go with a 5 or 5% inch diametered auger in the example 40-foot trough.

Water 93 enters the trough through a pipe at a water input point indicated by the arrow 102. The upper end of the trough is similarly completely open as seen at 99.

It will be seen that the open lower end of the trough, in effect, provides what can be called an opening in the area immediately above the auger as shown at 98 which opening is bounded by the trough sidewalls and bottom. The opening is formed by the fact that the lower end of the auger simply does not have an end wall whereby the end is open especially in the space immediately above the auger.

The mixture flowing in at the material input point 92 is from a source of a mixture of pieces of a heavier substance, which can be rock, 200, and of a lighter substance which can be coal, 210. The heavier substance 200 having a higher specific gravity than said lighter substance 210, both substances having a greater specitic gravity than water or other liquid supplied through pipe 100 whereby they will both sink or other liquid supplied through pipe 100 if otherwise unsupported.

The auger has a center axis and the trough closely but movably receives the auger.

The motor 26 drives the auger so that the rock therein is carried up the trough and out of the upper end of the trough, the desired movement of the pieces 200 and 210 of rock and coal and of water being such that substantially all pieces of the heavier substances, rock, sink down between and under the pieces of the lighter substance and into the flow-path of the auger and the rock is delivered out of the upper end of the trough by the auger while substantially all of those pieces 210 of the lighter substance, coal, because they are above the auger, are pushed by the water downward by gravity out of the open loweer end of the openended trough.

The sides of the trough extend above the axis 160 of the auger sufficiently to contain the pieces of rock and coal and the water. The inclination of the auger is at an acute angle with respect to the horizontal which is sufficent to cause enough movement of the pieces of rock 200 and coal 210 to allow the pieces of the heavier substance, rock, to sink under the pieces 210 of lighter substance, coal, and yet not so excessively as to substantially prevent pieces of the lighter substance, coal, from falling downwardly transversely of the length of the auger into the flow-path of the auger.

I processed 14 tons of mixed coal and rock through a separator of this description and out of the 14 tons I got 7 tons of rock and 7 tons of coal and did not find a single piece of coal in the rock or a single piece of rock in the coal.

The bottom end of the trough is open and preferably completely open so that a full flow of water out the bottom of the trough is possible, this flow is unrestricted by any part of the machine itself except the auger in the trough. I have found that this machine works perfectly without baffles, shaker, vibrator, or extra pipes. It is very simple. The trough is simply sufficiently unrestricted so that water will not collect in a relatively still condition in the trough or pool at its lower end whereby the water is turbulent on its upper side in the separation area A.

The water level in the area adjacent the lower end of the trough is substantially the same as the water level at a point which is three feet downstream of the material input point.

The lower end of the trough must be sufficiently open and the rate of water flow such that the flow of water down the trough and out of the open lower end of the trough is sufficiently unrestricted that all water portions above the auger are sufficiently turbulent along the separation area A for effectively stirring the mixture to substantially assist to bring about the described separation movements of heavier and lighter pieces of material, whereby no extensive pool of water is formed at the lower end of the trough so that there is sufficiency of water turbulence for separation of the materials. The water is delivered to the trough far enough from the lower end of the trough for helping to cause the desired separation movement of the pieces and water.

There is substantial flow of pieces of the lighter substance, coal, and water out of the open lower end of the trough in directions generally parallel to the length of the straight auger whereby substantial motion of pieces of coal, pieces of rock and of water takes place in the separation area A sufficiently to allow the pieces of rock substance to move by gravity downward transversely of the length of the auger between the pieces of coal into the flow-path of the auger. The respective means, later described, for delivering the mixture at 92, for delivering water at 102 and for driving the auger 20, all operate at rates for helping to cause the abovedescribed desired separation movement of the pieces 26M and 210 and water 93, the auger and the bottom of the trough being long enough below the mixture delivery point 92 and the water injection point 102 and inclined lengthwise at an acute angle with respect to the horizontal sufficiently to help cause the desired above-described separation movement of the pieces and water.

The auger is of a closed type having a substantially closed area between any of its outer flight portions and its center axis.

The majority of the water delivered to the trough preferably enters the trough above the center of the length of said trough.

It will be seen that the relative proportions of said auger diameter in inches to said trough length in inches are approximately in the ratio of five to the figure of 40 (feet) multiplied by 12 (inches-per-foot).

If an auger is driven excessively fast, there are two disadvantages, auger will jump up and down and beat the bottom of the trough until it wears it out. The other disadvantage is that the auger will throw too much water out of the top end of the trough and coal will go with it, because the mixture is screwed to top so that fast coal cannot separate.

Never in the history of auger separators has there ever been pool-less separator having water flowing turbulently all the way down to its lower end so that its upper surface is turbulent all the way down to its lower end, rather than calm-topped, like a pool.

The machine will separate lumps of material as big as the auger will carry out. An auger 5% inches in diameter will separate from 0 to 3 inch diametered lumps easil The level of the upper surface of the water in the separation area is approximately the same distance from the auger along the separation area and is inclined with respect to the horizontal all along the separation area at approximately the same angle with respect to the horizontal.

In FIG. 2 it will be seen that there are pieces of coal 210 and pieces of rock 200 sometimes in the swath of the auger at the lower end of the trough 60, but it is to be understood that as these pieces move upwardly lengthwise of the trough, the motion involved will cause the pieces of coal to come out of the auger area and be replaced by pieces of rock.

in FIG. l, at 300, can be seen a part of a support frame 300, the remainder of the frame being broken away since it is easily to be understood that it is supported on the ground 301 in an ordinary manner.

A suspension bracket 302 extends downwardly from the support frame 300 and is secured by a pivot bolt 304'to the trough 60 in a manner such that the trough 60 is free to pivot about a horizontal axis through the bolt 304, so that the upwardly and downwardly under the influence of a jack 312, having a handle 314, the jack 312 being rested on the ground surface 301, and

engaging an underside of the trough toward the upper end of the trough from the pivot bolt 304.

In the trough at a point spaced upwardly from the auger 241i and disposed along the trough upwardly from the material entry point 92, but preferably downwardly along the trough, from the water entry point 102, is a feeler 330, having an up-turned end 336 facing the lower end of the trough so that when an excess of material builds up under the feeler 330, the rigid feeler 330 tends to rise, causing a pivoting of a feeler support arm 332 attached thereto above a horizontal pivot bolt 334, attaching the arm 332 to the trough 60.

As the feeler 33th rises, the upper end of the arm 332 will move to the direction of the upper end of the trough Ml and will cause a switch 340 to open. The switch 340 is mounted on a bracket 342 by means of a spring 344 and the bracket 342 can be mounted in a stationery relationship with respect to the frame 300, such as by attachment to the funnel 90.

Above the funnel 9b is a material delivery belt conveyor 350 operated by a motor assembly 360 having a motor 362 which is electrical.

The motor 362, as best seen in FIG. 4, is attached to a power source wire 370, and is also connected to the other wire 372 of the pair of power source wires 370 and 372, by means of a wire 374 and a switch 340, which is disposed between the wires 372 and 374.

In operation it will be found that. no operator need be present, as the machine is running, because any overload of material coming in at the point 92 will tend to cause the feeler 336 to rise, opening the switch 340, and shutting off the conveyor motor 362. As soon as the material flow has gone down a bit so that it is not in excess of the desired level, the feeler 330 will cease to be supported by material therebeneath, the switch 340 will close and the conveyor 350 will once more deliver coal and rock mixture to the trough at the funnel 90.

The amount of water turbulence or water motion, in the separation area A is sufficient to cause the coal pieces but not the rock pieces to be held in suspension or supported by the moving, turbulent water in the same manner that dirt is supported in stirred water. The water motion or turbulence is carefully regulated, partly by its rate of imput, and partly by the angle of the trough, with respect to the horizontal, so that the water motion or turbulence is not sufficient to cause the rock to be supported by the moving water. This selective support is very important.

An open centered auger, if used in place of the closed type auger 2&1), would not work as good because coal and rock pieces would tend-to pass down hill through the middle of the auger, if it were open, reducing efficiency. The closed auger flight is complementally configured to cooperate with the semi-circular bottom zone of the trough in resisting movement of the rock in the bottom zone of the trough toward lower end 40.

If an auger 5 inches in diameter is operated at 131 revolutions per minute, when the auger is 40 feet long, and inclined at 10 with respect to the horizontal, then the machine with successfully separate the coal from rock, since i have successfully operated a machine in this way. But it is to be understood. that at 131 revolutions per minute there will be a lot of wear on the trough and the auger, and it is better that the revolutions per minute of the auger be or less to prevent the auger from wearing out too fast. However, since the machine just described would operate to separate coal at revolutions per minute of 200 or less, I wish it to be understood that my invention is not limited to the lower speeds of auger rotation.

Rocks may become wedged between the auger flight and the bottom of the trough tending to bind and stop the auger 20. To prevent such an occurrence the auger 20 is supported against movement in a direction downwardly and at right angles to the length of the auger only by the trough itself so that the auger is free to move upwardly away from the bottom of the trough to free any rock which might become caught between the auger flight and the bottom of the trough. Further, the drive pulley 24 associated with motor 26 is mounted upon a drive shaft 400 which is interconnected with the adjacent end of auger shaft 22 by a universal joint 430 which allows the upward movement of auger 20 to free any rock wedged between the trough and the auger. Drive shaft 400 is carried in suitable bearings such as 402 which may be mounted upon a suitable bracket (not shown) to thereby rotatably mount shaft 400 with respect to trough 60 and permit coupling of shaft 400 with shaft 22 of the auger 20.

I claim:

1. A machine for separating pieces of relatively light and heavy substances by use of a liquid of lesser specific gravity than either of said substances, said machine comprising:

an elongated, inclined, stationary trough having nor mally upper and lower ends, a bottom zone, and sidewalls extending upwardly from said bottom zone;

means for introducing a mixture of said pieces of light and heavy substances into said trough at a point intermediate said upper and lower ends thereof;

an elongated auger disposed generally within said bottom zone and configured to cooperate with said trough to resist movement of said pieces of substances in said bottom zone toward said lower end of the trough;

means for introducing said liquid into said trough for flow through said mixture of substances therein, the area between said sidewalls at the lower end of said trough being substantially free from obstructions to prevent collection of said liquid in a relatively still condition at said lower end of the trough and to allow unrestricted, relatively turbulent flow of said liquid along the trough and out of said lower end thereof,

said liquid introducing means being operable to deliver said liquid to the trough at a rate allowing said pieces of heavy substance to settle into said bottom zone while creating a flow of liquid in the trough above said auger of sufficient turbulence to hold said pieces of light substance in suspension above said auger for travel and discharge with said liquid out of said lower end of the trough; and

means for driving said auger whereby said pieces of heavy substance in said bottom zone travel toward said upper end of the trough against said turbulent flow of liquid.

2. The apparatus of claim 1, wherein said auger has a central shaft and a flight on said shaft substantially closed in area between the outer periphery of said flight and said shaft.

3. The apparatus of claim 1, wherein said liquid introducing means delivers said liquid to the trough at a point intermediate said upper end of said elongated trough and said point of introduction of said mixture of substances.

4. The apparatus of claim 3, wherein said point of introduction of said mixture of substances is approximately midway between said upper and lower ends of said trough.

5. The apparatus of claim 1, wherein said auger has a diameter of approximately 5 inches and the length of said trough is at least approximately 40 feet.

6. The apparatus of claim 1, wherein the relative proportions of the diameter of said auger to the length of said trough are approximately in the ratio of five to the figure of: 40 multiplied by 12.

7. The apparatus of claim 1, wherein said liquid introducing means is arranged relative to said trough to deliver said liquid thereto at rates substantially preventing liquid overflow of said upper end of said trough.

8. The apparatus of claim 1, wherein said auger is supported against movement in a direction downwardly and at a right angle to the length of the auger substantially only by engagement with said trough whereby said auger is free to move upwardly away from the bottom of said trough.

9. The apparatus of claim 8, wherein said means for driving said auger comprises a motor secured to said trough adjacent said upper end thereof said motor having a drive shaft, and universal joint means interconnecting said drive shaft and the adjacent end of said auger to drive the latter while allowing said auger to move upwardly away from the bottom of said trough.

10. The apparatus of claim 1, wherein means for introducing said mixture of substances into the trough includes power operated means controlling the rate of delivery thereof, a source of power, a switch, circuit means placing said switch in circuit with said source of power and with said power operated means so that said switch controls said power operated means, a feeler in said trough, means movably mounting said feeler for movements upwardly and downwardly as the level of said mixture of substances in the trough varies, said feeler being engageable with said switch whereby upward movement of said feeler when said mixture of substances in said trough is excessive causes said feeler to operate said switch to control said power-operated means to reduce introduction of said mixture of substance into said trough.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT N0. 1 3,739,911

DATED June 19, 1973 INVENTORQ) William D, Patch,

It is certified that error appears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

On the first page of the Patent under "Related U. S. Application Data", second line, after "abandoned" delete the period and add which was a continuation of application Serial No. 709, 975, filed March 4, 1968, abandoned Column 1, under "CROSS-REFERENCE" line 3, after "abandoned", delete the period and add which was a continuation of application Serial No. 709 ,975 filed March 4. 1968. abandoned Signed and Scaled this Thirty-first Day Of October 1978 [SEAL] Arrest:

Attesting Officer Commissioner of Patents and Trademarks 

1. A machine for separating pieces of relatively light and heavy substances by use of a liquid of lesser specific gravity than either of said substances, said machine comprising: an elongated, inclined, stationary trough having normally upper and lower ends, a bottom zone, and sidewalls extending upwardly from said bottom zone; means for introducing a mixture of said pieces of light and heavy substances into said trough at a point intermediate said upper and lower ends thereof; an elongated auger disposed generally within said bottom zone and configured to cooperate with said trough to resist movement of said pieces of substances in said bottom zone toward said lower end of the trough; means for introducing said liquid into said trough for flow through said mixture of substances therein, the area between said sidewalls at the lower end of said trough being substantially free from obstructions to prevent collection of said liquid in a relatively still condition at said lower end of the trough and to allow unrestricted, relatively turbulent flow of said liquid along the trough and out of said lower end thereof, said liquid introducing means being operable to deliver said liquid to the trough at a rate allowing said pieces of heavy substance to settle into said bottom zone while creating a flow of liquid in the trough above said auger of sufficient turbulence to holD said pieces of light substance in suspension above said auger for travel and discharge with said liquid out of said lower end of the trough; and means for driving said auger whereby said pieces of heavy substance in said bottom zone travel toward said upper end of the trough against said turbulent flow of liquid.
 2. The apparatus of claim 1, wherein said auger has a central shaft and a flight on said shaft substantially closed in area between the outer periphery of said flight and said shaft.
 3. The apparatus of claim 1, wherein said liquid introducing means delivers said liquid to the trough at a point intermediate said upper end of said elongated trough and said point of introduction of said mixture of substances.
 4. The apparatus of claim 3, wherein said point of introduction of said mixture of substances is approximately midway between said upper and lower ends of said trough.
 5. The apparatus of claim 1, wherein said auger has a diameter of approximately 5 inches and the length of said trough is at least approximately 40 feet.
 6. The apparatus of claim 1, wherein the relative proportions of the diameter of said auger to the length of said trough are approximately in the ratio of five to the figure of: 40 multiplied by
 12. 7. The apparatus of claim 1, wherein said liquid introducing means is arranged relative to said trough to deliver said liquid thereto at rates substantially preventing liquid overflow of said upper end of said trough.
 8. The apparatus of claim 1, wherein said auger is supported against movement in a direction downwardly and at a right angle to the length of the auger substantially only by engagement with said trough whereby said auger is free to move upwardly away from the bottom of said trough.
 9. The apparatus of claim 8, wherein said means for driving said auger comprises a motor secured to said trough adjacent said upper end thereof said motor having a drive shaft, and universal joint means interconnecting said drive shaft and the adjacent end of said auger to drive the latter while allowing said auger to move upwardly away from the bottom of said trough.
 10. The apparatus of claim 1, wherein means for introducing said mixture of substances into the trough includes power operated means controlling the rate of delivery thereof, a source of power, a switch, circuit means placing said switch in circuit with said source of power and with said power operated means so that said switch controls said power operated means, a feeler in said trough, means movably mounting said feeler for movements upwardly and downwardly as the level of said mixture of substances in the trough varies, said feeler being engageable with said switch whereby upward movement of said feeler when said mixture of substances in said trough is excessive causes said feeler to operate said switch to control said power-operated means to reduce introduction of said mixture of substance into said trough. 